Looper operating mechanism for sewing machines



F. LUTZ LOOPER OPERATING MECHANISM FOR SEWING MACHINES 2 Sheets-Sheet 1 Filed Feb. 5. 1929 Oct. 13, 1931. F, LUTZ 1,827,594

LOOPER OPERATING MECHANISM FOR SEWING MACHINES Filed Feb. 5. 1929 2 Sheets-Sheet 2 gmento'c Feline/ch Lurz.

dub was the f LOOPER OPERATING MECHANISM FOR SEWING MACHINES Application filed February 5, 1929, Serial No.

The invention relates to new and useful improvements in a looper operating mechanism for sewing machines, and more particularly to a mechanism whereby a thread carrying looper beneath the work support is oscillated through devices connected to the needle lever mounted on the overhanging arm of the machine. I

An object of the invention is to provide an operating mechanism for the looper which is connected to the needlelever at a point adjacent the connection of the actuating means therefor. I

A further object of the invention is to provide a above character wherein the actuatin devices are so-constructed as to give a dwel to the looper at the forward end of its stroke.

A further object of the invention is to provide a looper operating mechanism of the above character which is provided with means whereby the extent of the dwell given to the looper at the forward end of its stroke and the degree of acceleration given to the looper at the rear end of its stroke may be varied.

A still further object of the invention is to' provide a looper operating mechanism of the above type which is so constructed and arranged that the parts above the work support are substantially housed within the standard and overhanging arm.

In the drawings:

Fig. 1 is a view showing in full lines a needle actuating mechanism and a looper operating mechanism embodying the 1mprovements, and in broken lines the movement of the parts andthe frame of the machine.

Fig. 2 is a vertical sectional view through rame of the machine, the needle lever being sectioned at the point where the looper operating mechanism is connected thereto.

Fig. 3 is a detail showing in plan a part of the needle operating lever, the actuating device therefor, and the ball stud connection for operating the looper.

In the drawings which show ment of the invention, frame is indicated at one embodia sewlng machlne This sewing malooper operating mechanism of the 837,606, and in Germany February 8, 1928.

chine frame is provided with an overhang- I mg arm in which is mounted a needle bar I carrying a needle h. The main shaft a Is journaled in suitable bearings in the bed of the machine and is provided with a crank intermediate its ends. coo erating with the crank is connected to a ba stud d at the end of the needle lever e.

he needle lever e is fulcrumed at f within the overhanging arm and is connected'at its other end a: b the needle bar. shaft is cated.

Located beneath the work sup ort and cooperating with the needle h is a t read carrying looper z. The looper is mounted on a carrier is pivoted at Z to a looper support of the usual character.

he present invention is directed particularly to the means for oscillating the looper for causing said thread carryin loo er to move into and out of the needle trea loop. Theneedle lever e is a lever of the first order and fulcrumed intermediate its ends. The arm r of the needle lever carries the ball stud d with which the actuating mechanism for operating the needle lever is connected.

The lever adjacent the ball vided with an enlarged head larged head of the lever is formed with a T-shaped slot 4;. The slot extends substantially in a direction at right angles to the length of the lever. Adjustably mounted in this T-shaped slot 4) is a T-head M which is capable of adjustment in the slot and may Thus it is that when the main rotated, the needle lever is reciprobe secured in various adjusted positions therein. Mounted on this T-head A link 9 is provided with a head t which cooperates with this ball stud s. The other end of the link q is connected to a head If. The link 9 has right and left threaded connections with the heads t and t, which provides a means for lengthening or shortening the link.

lever arm 79 is carried by a shaft n mounted in suitable bearings in the standard of the machine. At the outer end of the p is a ball stud with which the head t cooperates. Also mounted on this shaft n is a lever arm 0 which carries a ball stud at its u is a ball stud 8.

lever arm the ball 'stud son the end of the needle lever I 55 dwell given to the at the lower end of the lever arm 0.

with t tends through link q and the stroke.

the ball stud s at lower end. A link m is provided with a head m at one end which en ages a ball stud on the looper carrier 70 and it is also provided with a head m" which engages the all stud The link has ri ht and left hand threaded connections hese heads m and m. This provides a means whereby the link may be, lengthened and shortened. I

It will be noted that the needle lever is located within the hollow overhanging arm. the actuating means for the needle lever exthe hollow; standard to its connection with the actuating shaft.

lever arm pare also located within the hollow arm and hollow standard. The arm '0,however, is outside of the standard Y and extends beneath the cloth plate where it is connected to the link which oscillates the 20 looper.

I From the abovev arrangement of the parts, it. will be noted that the entire space heneath the overhanging arm is free from obstruction for-the passing of the work which .is being and hollow standard and the one part that is not is at one side thereof. 7 I

The purposeof adjusting the position of is to vary the dwell given to the looper at the forward end of its stroke and the acceleration given to the looper at the rear end of its 441 the linkig to ths lever arm p.

As shown in Fig. 1 in full lines, the ball stud is very close to this line and the looper is at the forward end of its stroke. In fact, the stud may move past the line and this is 45 for the-purpose of giving a dwell to the loop er at. the forward end of its stroke- In the heavy broken dash line the position of the parts when the looper is at the rear end .of

1 its stroke is indicated. It will be noted that this time is at its farthest distance from the line referred to and the looper will come to the rear end of its stroke and quickly start on its forward movement.

When it is desired to decrease the amount of looper, the ball stud s is adjusted away from this line passing through the fulcrum of the lever and the connection of the link q to the lever arm p. By this adjustment, the ball stud does not approach as near the line when the looper reaches the forward end of its stroke and, therefore, there will be a less dwell given to the looper.

It is true that this shifting of the ball stud will vary the oscillating position of the loop- 6 er, but the link m can be very readily length- The It is noted that when stitched. The parts above the cloth plate are all substantiallyhoused within the The arm r of the needle lever and the link q form a toggle arrangement and the given to the looper at the and to the looper carrier ward end of its stroke the ball stud will pass slightly across the dead center line and thus the dwell given to the looper increased.

From the above itwill be apparent that a looper actuating means. has been provided which may be connected to the usual two-arm needle actuating leverandthe connection may be made to said lever adjacent the driving connection therefor, and thus the parts above the. work support for operating the looper substantially housed within the standard carrying the overhanging arm.' It will also be apparent that the mechanismis very simple and readily accessible for adjustment. the looper is at the forward end of its stroke, the'lever arm 0 and link m are likewise nearer a dead center line passing through the axis of the shaft '1 and the connection of the link on to the looper carrier, and this will slow up the movement of the looper.

It is obvious that minor changes inthe details of construction may be made without departing from the spirit of as set forth in the appended claims.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent, is

l. Ina sewing machine the combination of aneedle bar, a needle carried thereby, a needle lever pivoted intermediate its ends and connected to said needle bar for reciprocating the same, a driving connection to said needle lever at the end thereof opposite the needle bar, a thread carrying looper cooperating with said needle, an oscillating member, a link connected to said oscillating member and to a ball stud adj acent the actuated end of the needle lever, a link connecting said member to said looper for oscillating the same, and means whereby said ball stud may be adjusted on said needle lever in a direction substantially at right angles to the length of the lever for varying the dwell forward end of its stroke.

2. In a sewing machine the combination of a needle bar, a needle carried thereby, a needle lever pivoted intermediate its ends and connected to said needle bar for reciprocating the same, a driving connectionto said needle lever at the end thereof opposite th needle bar, a looper, a looper carrier there for,a shaft, lever arms arried by the shaf and projecting therefrom, a link connected t one of said needle lever arms and to a bal studcarried by the actuated end of the needl lever, a link connected to the other lever arr for oscillating th the invention looper, said lever arm connected to the needle lever' being disposed so that the ball stud moves. toward a dead center line when the looper is moved into the needle thread 100 and means for shifting said ball stud on sa1 needle lever toward and from said dead center line, and means whereby said looper may be positioned for oscillation in substantially the same path for all positions of adjustment of the ball stud.

In a sewing machine the combination of a needle bar, a needle carried thereby, a nee dle lever pivoted intermediate its ends and connected to said needle bar for reciprocating the same, a driving connection to said needle lever at the end thereof opposite the needle bar, a thread carrying looper cooperating with said needle, a looper carrier for said looper, said needle lever at the actuated end thereof having a head provided with a T- sha-ped slot, a T-shaped member carrying a ball stud adjustable in said slot, said s'lot being disposed so that the ball stud may be adjusted toward and from the longitudinal axis of the lever, a shaft, a lever arm con nected to said shaft, a link connecting said lever arm to the ball stud, a second lever arm connected to said shaft, and a link connecting said last-named lever arm with the looper carrier, said last-named link having an intermediate portion with right and left hand thread connections.

4. In a sewing machine, the combination of a needle bar, a needle carried thereby, a

substantially straight needle lever pivoted intermediate its ends and connected to the needle bar for reciprocating the same, actuating means connected to the needle lever at the end thereof opposite the needle bar, a thread carrying looper cooperating with the needle, an osclllating member, a link connecting said'oscillating member to thelooper, a ball stud adjacent the connection between the needle lever and its actuating means, and a link connecting said ball stud to the oscillating member, said link being adapted to move into substantial alinement with the needle lever when the looper is at the forwardend of its stroke. r k

In testimony whereof, I aflix my si FRIEDRICH'L ature. TZ. l 

